This invention relates to apparatus for positioning a workpiece in a work station, and more particularly to apparatus for positioning multiple cutters on an elongate reach of saw chain adjacent spaced sharpeners with slack being maintained in the portions of the reach of chain between the sharpeners.
A saw chain includes a plurality of elongate links which are pin-connected to each other at adjacent sets of their ends. The cutter elements in the chain have bit portions which extend above remainder portions of the chain and have chisel-like forwardly facing cutting edges which perform the cutting during operation of the saw chain. In the past, such cutters have been sharpened individually by apparatus in which the chain is advanced merely one cutter link at a time for sharpening.
Sharpening of only one cutter at a time, however, is more time consuming and less efficient than is the sharpening of a plurality of cutters with a plurality of sharpeners spaced along a length of the chain. It has been found however, that multiple station sharpening cannot be performed effectively merely by pulling the chain along a path adjacent the plural sharpeners. When a saw chain is tensed and pulled along a path from one end the variations in positioning of the pins in the chain and the variations which occur in the sizes of the bores for receiving the pins and the diameters of the pins themselves accumulate over the reach of chain. Such accumulated variations in the chain are sufficient to defeat any attempt to position the spaced-apart cutters precisely relative to the plural sharpeners merely by pulling the chain along the path.
A general object of the present invention is to provide novel multiple station sharpening apparatus for sharpening cutters distributed along a reach of saw chain, which apparatus is operable to precisely position multiple cutters for efficient and rapid sharpening.
More specifically an object of the invention is to provide such sharpening apparatus in which selected cutters in a reach of chain are engaged by cutter engaging elements to produce a degree of slack in portions of the reaches therebetween and, while maintaining such slack in the portions of the chain between the selected cutters, conveying the cutters to the sharpening stations adjacent the sharpeners, at which stations they may be precisely positioned for sharpening. With slack produced between selected sharpeners, precise positioning of the cutters in multiple sharpening stations may be accomplished.
Another object of the present invention is to provide positioning means for conveying a workpiece into an approximate desired position in a work station, and through the use of workpiece holding mechanism, precisely positioning and holding the workpiece in the station for operation.